A study of batch and column adsorption using A. jiringa seed shell as a natural adsorbent to remove methylene blue from aqueous solution was carried out. This study aimed to determine the effectiveness of A. jiringa s...A study of batch and column adsorption using A. jiringa seed shell as a natural adsorbent to remove methylene blue from aqueous solution was carried out. This study aimed to determine the effectiveness of A. jiringa seed shell in removing methylene blue as well as to determine the isotherm and adsorption kinetics of methylene blue by A. jiringa seed shells. Parameters in the batch study showed optimum pH for adsorption was at pH 7 with the optimum contact time of 60 minutes whereas the adsorbent dose obtained was 12 g/l. The percentage removal of methylene blue increased with elevated temperature while the ionic strength reduced the adsorption capacity in the dye uptake. Langmuir isotherm was suitable for this study rather than Freundlich model due to the higher regression value: R2 = 0.9999. The most suitable kinetic model for this study was the pseudo second order, compared to pseudo first order, Elovich and intra particle with the value of regression: R2 = 0.9158. This column adsorption study used several different flow rates: 15 mL/min, 18 mL/min, 21 mL/min, 24 mL/min and 27 mL/min for 75 minutes long. The breakthrough time was lesser: 10 minutes in higher flow rates (24 mL/min and 27 mL/min), which indicated the shorter time for the adsorbent to be saturated. Thomas and Yoon & Nelson’s models were proven to be more suitable compared to Bohart-Adams model for the fixed bed adsorption study.展开更多
Egusi seed shells (ESS) were used as precursor for the preparation of two activated carbons (ACs) following H3PO4 and ZnCl2 activation. The effect of factors controlling the preparation of ACs such as chemical activat...Egusi seed shells (ESS) were used as precursor for the preparation of two activated carbons (ACs) following H3PO4 and ZnCl2 activation. The effect of factors controlling the preparation of ACs such as chemical activating agent concentration (2 - 10 M), activation temperature (400°C - 700°C) and residence time (30 - 120 min) were optimized using the Box-Behnken Design (BBD). The optimized activated carbons based H3PO4 (ACP) and ZnCl2 (ACZ) were characterized by N2 adsorption, elemental analysis, atomic force microscopy (AFM), Boehm titration and Fourier transformed infrared (FTIR) techniques. The specific surface area was found to be 1053.91 and 1009.89 m2·g-1 for ACP and ACZ respectively. The adsorbents had similar surface functionalities and were both microporous. The effect of various parameters such as initial pH, concentration, and contact time on the adsorption of nitrate ions on ACP and ACZ in aqueous solution was studied. ACZ demonstrated better adsorption capacity (8.26 mg·g-1) compared to ACP (5.65 mg·g-1) at the same equilibrium time of 20 min. The adsorption process was governed by a “physical interactions” phenomenon for both adsorbents.展开更多
Mucuna pruriens seed shells (abundantly available agricultural waste) were processed, treated and activated using 60% orthophosphoric acid for removal of congo red and malachite green from an aqueous solution. Its phy...Mucuna pruriens seed shells (abundantly available agricultural waste) were processed, treated and activated using 60% orthophosphoric acid for removal of congo red and malachite green from an aqueous solution. Its physicochemical properties and its removal efficiencies on the textile dyes were determined. The effect of particle size, adsorbent dose, initial pH of solution, adsorbate concentration and contact time on the process of adsorption was investigated. The equilibrium, kinetic and thermodynamic properties of the dyes removal were also investigated. The experi-mental data were modeled using linear regression method of analysis. The correlation coefficient was used as a criterion for model adequacy and acceptance. Sum of squares error was used to val-idate the isotherm models. The pseudo second-order kinetic model was found to best correlate the experimental data. The intraparticle diffusion is not the only rate controlling step in the process. The experimental data were found to follow the Langmuir, Freundlich and Tempkin isotherm models. The negative free energy indicated that the adsorption processes were spontaneously feasible. The process of adsorption has been found to be endothermic in nature. The removal of malachite green was found to be more spontaneous and feasible than the removal of congo red on the adsorbent. From the study it was deduced that the Mucuna pruriens seed shells activated with phosphoric acid were found to be a good adsorbent for the treatment of textile wastewater con-taining congo red and malachite green.展开更多
The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth ...The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.展开更多
The conversion of agricultural residual biomass into biochar as a sulfur host material for Li-S batteries is a promising approach to alleviate the greenhouse effect and realize waste resource reutilization.However,the...The conversion of agricultural residual biomass into biochar as a sulfur host material for Li-S batteries is a promising approach to alleviate the greenhouse effect and realize waste resource reutilization.However,the large-scale application of pristine biochar is hindered by its low electrical conductivity and limited electrocatalytic sites.This paper addressed these challenges via the construction of Fe-N co-doped biochar(Fe-NOPC)through the copyrolysis of sesame seeds shell and ferric sodium ethylenediaminetetraacetic acid(NaFeEDTA).During the synthesis process,NaFeEDTA was used as an extra carbon resource to regulate the chemical environment of N doping,which resulted in the production of high contents of graphitic,pyridinic,and pyrrolic N and Fe-Nx bonds.When the resulting Fe-NOPC was used as a sulfur host,the pyridinic and pyrrolic N would adjust the surface electron structure of biochar to accelerate the electron/ion transport,and the electropositive graphitic N could be combined with sulfur-related species via electrostatic attraction.Fe-Nx could also promote the redox reaction of lithium polysulfides due to the strong Li-N and S-Fe bonds.Benefiting from these advantages,the resultant Fe-NOPC/S cathode with a sulfur loading of 3.8 mg·cm^(-2)delivered an areal capacity of 4.45 mAh·cm^(-2)at 0.1C and retained a capacity of 3.45 mAh·cm^(-2)at 1C.Thus,this cathode material holds enormous potential for achieving energy-dense Li-S batteries.展开更多
以牡丹籽壳为原料,利用大孔树脂和C18反相键合硅胶柱(C18柱)联合分离短叶松素,回收率为(98.33±0.64)%。用70%(体积分数)乙醇提取牡丹籽壳粗黄酮(Mu Dan Ke Flavonoids,MDKF),得率最高为(10.54±0.13)%;比较了6种大孔树脂(AB-8...以牡丹籽壳为原料,利用大孔树脂和C18反相键合硅胶柱(C18柱)联合分离短叶松素,回收率为(98.33±0.64)%。用70%(体积分数)乙醇提取牡丹籽壳粗黄酮(Mu Dan Ke Flavonoids,MDKF),得率最高为(10.54±0.13)%;比较了6种大孔树脂(AB-8、S-8、DM301、HPD600、HPD100和D101)的吸附率和解析率,发现S-8大孔树脂的吸附率和解析率最佳,分别为83.47%和84.46%;优化S-8大孔树脂分离MDKF的最佳条件为:上样液质量浓度1.6 mg/mL,上样液流速2.0 mL/min,洗脱剂乙醇体积分数60%,洗脱液流速1.5 mL/min,洗脱液体积100 mL;对经过C18柱分离后的组分进行LC-MS分析得到短叶松素,回收率为(98.33±0.64)%;分离前后抗氧化能力比较:C18纯化物>S-8大孔树脂纯化物>MDKF粗提物;分子对接实验表明,短叶松素与超氧化物歧化酶、过氧化氢酶、过氧化物酶、谷胱甘肽过氧化物酶均有结合能力,过氧化氢酶的结合能力最强为-9.1 kcal/mol。实验表明,短叶松素具有较好的抗氧化能力,可作为食品、药品或化妆品等抗氧化剂的添加,应用前景非常广泛,对牡丹籽壳的进一步开发利用提供理论支持。展开更多
文摘A study of batch and column adsorption using A. jiringa seed shell as a natural adsorbent to remove methylene blue from aqueous solution was carried out. This study aimed to determine the effectiveness of A. jiringa seed shell in removing methylene blue as well as to determine the isotherm and adsorption kinetics of methylene blue by A. jiringa seed shells. Parameters in the batch study showed optimum pH for adsorption was at pH 7 with the optimum contact time of 60 minutes whereas the adsorbent dose obtained was 12 g/l. The percentage removal of methylene blue increased with elevated temperature while the ionic strength reduced the adsorption capacity in the dye uptake. Langmuir isotherm was suitable for this study rather than Freundlich model due to the higher regression value: R2 = 0.9999. The most suitable kinetic model for this study was the pseudo second order, compared to pseudo first order, Elovich and intra particle with the value of regression: R2 = 0.9158. This column adsorption study used several different flow rates: 15 mL/min, 18 mL/min, 21 mL/min, 24 mL/min and 27 mL/min for 75 minutes long. The breakthrough time was lesser: 10 minutes in higher flow rates (24 mL/min and 27 mL/min), which indicated the shorter time for the adsorbent to be saturated. Thomas and Yoon & Nelson’s models were proven to be more suitable compared to Bohart-Adams model for the fixed bed adsorption study.
文摘Egusi seed shells (ESS) were used as precursor for the preparation of two activated carbons (ACs) following H3PO4 and ZnCl2 activation. The effect of factors controlling the preparation of ACs such as chemical activating agent concentration (2 - 10 M), activation temperature (400°C - 700°C) and residence time (30 - 120 min) were optimized using the Box-Behnken Design (BBD). The optimized activated carbons based H3PO4 (ACP) and ZnCl2 (ACZ) were characterized by N2 adsorption, elemental analysis, atomic force microscopy (AFM), Boehm titration and Fourier transformed infrared (FTIR) techniques. The specific surface area was found to be 1053.91 and 1009.89 m2·g-1 for ACP and ACZ respectively. The adsorbents had similar surface functionalities and were both microporous. The effect of various parameters such as initial pH, concentration, and contact time on the adsorption of nitrate ions on ACP and ACZ in aqueous solution was studied. ACZ demonstrated better adsorption capacity (8.26 mg·g-1) compared to ACP (5.65 mg·g-1) at the same equilibrium time of 20 min. The adsorption process was governed by a “physical interactions” phenomenon for both adsorbents.
文摘Mucuna pruriens seed shells (abundantly available agricultural waste) were processed, treated and activated using 60% orthophosphoric acid for removal of congo red and malachite green from an aqueous solution. Its physicochemical properties and its removal efficiencies on the textile dyes were determined. The effect of particle size, adsorbent dose, initial pH of solution, adsorbate concentration and contact time on the process of adsorption was investigated. The equilibrium, kinetic and thermodynamic properties of the dyes removal were also investigated. The experi-mental data were modeled using linear regression method of analysis. The correlation coefficient was used as a criterion for model adequacy and acceptance. Sum of squares error was used to val-idate the isotherm models. The pseudo second-order kinetic model was found to best correlate the experimental data. The intraparticle diffusion is not the only rate controlling step in the process. The experimental data were found to follow the Langmuir, Freundlich and Tempkin isotherm models. The negative free energy indicated that the adsorption processes were spontaneously feasible. The process of adsorption has been found to be endothermic in nature. The removal of malachite green was found to be more spontaneous and feasible than the removal of congo red on the adsorbent. From the study it was deduced that the Mucuna pruriens seed shells activated with phosphoric acid were found to be a good adsorbent for the treatment of textile wastewater con-taining congo red and malachite green.
基金Project(2000E0008Z) supported by Natural Science Foundation of Yunnan Province
文摘The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.
基金supported by the National Natural Science Foundation of China(No.21808053)the Postgraduate Scientific Research Innovation Project of Hunan Province,China(No.CX20210659)。
文摘The conversion of agricultural residual biomass into biochar as a sulfur host material for Li-S batteries is a promising approach to alleviate the greenhouse effect and realize waste resource reutilization.However,the large-scale application of pristine biochar is hindered by its low electrical conductivity and limited electrocatalytic sites.This paper addressed these challenges via the construction of Fe-N co-doped biochar(Fe-NOPC)through the copyrolysis of sesame seeds shell and ferric sodium ethylenediaminetetraacetic acid(NaFeEDTA).During the synthesis process,NaFeEDTA was used as an extra carbon resource to regulate the chemical environment of N doping,which resulted in the production of high contents of graphitic,pyridinic,and pyrrolic N and Fe-Nx bonds.When the resulting Fe-NOPC was used as a sulfur host,the pyridinic and pyrrolic N would adjust the surface electron structure of biochar to accelerate the electron/ion transport,and the electropositive graphitic N could be combined with sulfur-related species via electrostatic attraction.Fe-Nx could also promote the redox reaction of lithium polysulfides due to the strong Li-N and S-Fe bonds.Benefiting from these advantages,the resultant Fe-NOPC/S cathode with a sulfur loading of 3.8 mg·cm^(-2)delivered an areal capacity of 4.45 mAh·cm^(-2)at 0.1C and retained a capacity of 3.45 mAh·cm^(-2)at 1C.Thus,this cathode material holds enormous potential for achieving energy-dense Li-S batteries.
文摘以牡丹籽壳为原料,利用大孔树脂和C18反相键合硅胶柱(C18柱)联合分离短叶松素,回收率为(98.33±0.64)%。用70%(体积分数)乙醇提取牡丹籽壳粗黄酮(Mu Dan Ke Flavonoids,MDKF),得率最高为(10.54±0.13)%;比较了6种大孔树脂(AB-8、S-8、DM301、HPD600、HPD100和D101)的吸附率和解析率,发现S-8大孔树脂的吸附率和解析率最佳,分别为83.47%和84.46%;优化S-8大孔树脂分离MDKF的最佳条件为:上样液质量浓度1.6 mg/mL,上样液流速2.0 mL/min,洗脱剂乙醇体积分数60%,洗脱液流速1.5 mL/min,洗脱液体积100 mL;对经过C18柱分离后的组分进行LC-MS分析得到短叶松素,回收率为(98.33±0.64)%;分离前后抗氧化能力比较:C18纯化物>S-8大孔树脂纯化物>MDKF粗提物;分子对接实验表明,短叶松素与超氧化物歧化酶、过氧化氢酶、过氧化物酶、谷胱甘肽过氧化物酶均有结合能力,过氧化氢酶的结合能力最强为-9.1 kcal/mol。实验表明,短叶松素具有较好的抗氧化能力,可作为食品、药品或化妆品等抗氧化剂的添加,应用前景非常广泛,对牡丹籽壳的进一步开发利用提供理论支持。